LAVOISIER. 37 



microscope, and he is well provided ; and though the instru- 

 ments necessary to the astronomer are costly, they too are 

 for the most part unchanging. But men who devote them- 

 selves to new lines of chemical investigation frequently require 

 instruments to be devised, and, what is still more difficult, the 

 wherewithal to pay for them. 



Lavoisier, at the period to which this brings me, was en- 

 gaged in proving what has since become a truth in the mouth 

 of every moderately educated person, namely, that the dia- 

 mond and charcoal are in composition identical. An investiga- 

 tion so curious made great stir at the time. Our countryman 

 Priestley, and the celebrated French chemist Berthollet, were 

 appointed to come to the laboratory of Lavoisier, and see the 

 experiments. Berthollet had already arrived, as I have said, 

 but Priestley was yet absent. 



It was evening. A large argand lamp, having its rays 

 cast downwards by a shade, played upon some diamonds laid 

 on a piece of black paper, ready to be sacrificed to Lavoisier's 

 splendid though expensive discovery. 



6 It is well Robespierre does not know of this,' said Ber- 

 thollet, a smile lighting up his large features, which seemed 

 as if they had been chiselled out of a rock ; ' or it would make 

 work for the Louisette.'* 



6 We chemists are not high game enough for the monsters,' 

 replied Lavoisier. ' These are indeed fearful times ! Ugh !' 

 continued he, shuddering ; ' what the end will be, I know 

 not.' 



( It seems,' replied Berthollet, smiling, ' that some sort of 

 revolutionary infection is in the air : even you, my friend, are 

 struck with the malady.' 



Indeed, few persons have been more revolutionary than 



* The instrument of death invented by Dr. Guillotin, and now univer- 

 sally known as the guillotine, was for a time denominated the Louisette, 

 because it was the deputy Louis who first made himself acquainted with its 

 capabilities, and furnished a report upon them to the National Assembly. 



